Evaluation of EN15193-1 on energy requirements for artificial lighting against Radiance-based DAYSIM

Example-based dynamic façade design using the facade daylighting performance improvement (FDPI) indicator

“…Since approximately 30%-50% of the total commercial building electricity demand is used for artificial lighting (Yang et al 2021) with significant variation from one building to another (Krarti 2016), and taking into account that lighting energy savings regarding daylight harvesting vary from 20% to 87% (Yu and Su 2015), the addition of the energy savings aspect to the FDPI might be beneficial. Since daylight penetration solely is not enough to lead energy savings automatically, unless it is linked to shading and lighting control strategies (Akimov et al 2021a), the dynamic façade systems may play an important role in the daylighting and artificial lighting systems regulation (Rafsanjani et al 2015).…”

“…Similarly, to make a multi-objective framework for the dynamic façade design, the methodology proposed in this research can be extended by the parameter that accounts for the artificial lighting energy demand evaluation. The inclusion of the LENI (Akimov et al 2021a) in the FDPI methodology is an efficient way of creating universal parameter that would be useful for detailed dynamic façade analysis from both daylighting performance and energyefficiency points of view. The LENI inclusion would not bring any conflict to the FDPI-based daylighting performance evaluation since the basic LENI calculation, proposed by the European Normative EN15193-1:2017 (2017) includes the daylight availability estimation in the zone under evaluation.…”

“…For this particular research, the choice of the threshold value of DA metric was related to the comfortable illuminance level on the working plane for office workers. The research by Akimov et al (2021a) defines that the comfortable illuminance level on the working plane set for an office building is 500 lx. Therefore, the authors set a DA with a threshold of 500 lx (DA_500).…”

“…The main parameter constituting the LENI is the estimated lighting energy W L,t required to provide a zone of the building with adequate illumination. As it is defined by EN 15193-1:2017 (2017) and Akimov et al (2021a) W L,t , among other factors, depends on the daylight dependency factor F D that, being a function of building location and geometry along with openings geometry, obstructions presence, shading device presence/absence and glazing properties, denotes the daylight availability in the zone under evaluation.…”

“…As it is set in the experiment from Akimov et al (2021a), the artificial light is turned on only when the mean illuminance met on the task plain is below 500 lx. This means that LENI is in the direct dependence with DA_500 (which indicates the percentage of the occupied hours of the year when an illuminance of 500 lx is met by daylight alone).…”